ppc

Pay Per Click (PPC)
Pay Per Click (PPC) is an Internet advertising model used on search engines, advertising networks, and content sites, such as blogs, in which advertisers pay their host only when their ad is clicked. With search engines, advertisers typically bid on keyword phrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system.
Websites that utilize PPC ads will display an advertisement when a keyword query matches an advertiser’s keyword list, or when a content site displays relevant content. Such advertisements are called sponsored links or sponsored ads, and appear adjacent to or above organic results on search engine results pages, or anywhere a web developer chooses on a content site.

Additional Information
Find below the two models of PPC :

• Flat-Rate PPC Model – In the flat-rate model, the advertiser and publisher agree upon a fixed amount that will be paid for each click.
• Bid-Based PPC Model – In the bid-based model, the advertiser signs a contract that allows them to compete against other advertisers in a private auction hosted by a publisher or, more commonly, an advertising network. Each advertiser informs the host of the maximum amount that he or she is willing to pay for a given ad spot (often based on a keyword), usually using online tools to do so. The auction plays out in an automated fashion every time a visitor triggers the ad spot. Although many PPC providers exist, Google AdWords, Yahoo! Search Marketing, and Microsoft adCenter are the three largest network operators, and all three operate under a bid-based model.